from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
import os
import sys
from pathlib import Path

# 添加项目根目录到Python路径
sys.path.insert(0, str(Path(__file__).parent.parent))

from app.core.database import Base
from app.core.config import settings

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# 设置数据库URL
config.set_main_option("sqlalchemy.url", settings.DATABASE_URL)

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
target_metadata = Base.metadata

# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Run migrations in 'online' mode with enhanced connection pool settings.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    # 获取配置项
    config_section = config.get_section(config.config_ini_section)
    
    # 添加连接池配置
    config_section.update({
        "pool_size": config.get_main_option("pool_size") or "5",
        "max_overflow": config.get_main_option("max_overflow") or "10",
        "pool_timeout": config.get_main_option("pool_timeout") or "30",
        "pool_recycle": config.get_main_option("pool_recycle") or "3600",
    })
    
    connectable = engine_from_config(
        config_section,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=True,
            compare_server_default=True,
            render_as_batch=True,
            # 迁移配置选项
            version_table="alembic_version",
            version_table_schema=None,
            user_module_prefix=None,
            # 生成配置选项
            include_schemas=False,
            include_object=None,
            # 脚本相关选项
            process_revision_directives=None,
            # 事务处理
            transaction_per_migration=False,
            # 性能优化
            literal_binds=False,
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()